Switch to ansible_hostname in calico

For consistancy with kubernetes services we should use the same
hostname for nodes, which is 'ansible_hostname'.

Also fixing missed 'kube-node' in templates, Calico is installed
on 'k8s-cluster' roles, not only 'kube-node'.

roles/network_plugin/calico/templates/cni-calico.conf.j2

@@ -1,7 +1,7 @@
 {
   "name": "calico-k8s-network",
 {% if not legacy_calicoctl %}
-  "hostname": "{{ inventory_hostname }}",
+  "hostname": "{{ ansible_hostname }}",
 {% endif %}
   "type": "calico",
   "etcd_endpoints": "{{ etcd_access_endpoint }}",